What Does P041B Mean?
The PCM has determined that the exhaust gas recirculation temperature sensor B signal is not performing within the expected range. The sensor may be responding too slowly, reading an implausible value for current conditions, or not changing as expected when the EGR valve opens. This indicates the sensor may be partially functional but providing unreliable data. The driver will see the MIL and may experience slight performance issues under load.
Common Causes
35%
Carbon-fouled EGR temperature sensor B giving sluggish or skewed readings
25%
EGR valve not opening properly, causing sensor to not see expected temperature change
20%
Degraded EGR temperature sensor with slow response time
12%
Restricted EGR passage reducing exhaust gas flow past the sensor
8%
High-resistance connection in the sensor circuit affecting signal accuracy
Diagnostic Steps
1
Monitor the EGR temperature sensor B PID on the scan tool. With the engine at operating temperature and EGR commanded off, note the baseline temperature. Then command the EGR valve open — the temperature should rise 50-100°F within 30 seconds.
2
If the temperature does not rise when EGR is commanded open, verify the EGR valve is actually opening by monitoring EGR valve position PID or visually inspecting valve movement.
3
Remove the EGR temperature sensor and inspect the probe for heavy carbon deposits. Clean with a soft brush and carburetor cleaner, or replace if heavily fouled.
4
Check the EGR passage for carbon restriction by looking into the port with a flashlight or using a thin wire to probe the passage. A severely restricted passage can prevent exhaust gas from reaching the sensor.
5
If the sensor and passages are clean and the EGR valve operates correctly, replace the EGR temperature sensor B — the thermistor element may have drifted out of specification.
Estimated Repair Cost
$100 - $400
Parts + labor, varies by vehicle and location
The PCM has determined that the exhaust gas recirculation temperature sensor B signal is not performing within the expected range. The sensor may be responding too slowly, reading an implausible value for current conditions, or not changing as expected when the EGR valve opens. This indicates the se...
The most common cause of P041B (Exhaust Gas Recirculation Temperature Sensor "B" Circuit Range/Performance) is: Carbon-fouled EGR temperature sensor B giving sluggish or skewed readings
Typical repair costs for P041B range from $100 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Generally safe to drive, but the PCM may disable or incorrectly manage EGR flow. This could cause increased NOx emissions and potential detonation under high-load conditions. Avoid towing or sustained high-speed driving until the issue is resolved.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P041B to identify the root cause.
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Quick Info
Category
Powertrain
System
Exhaust Gas Recirculation (EGR) System
Difficulty
Type
Generic (SAE)
Recommended Tools
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